Utilizing a technique recently developed by the principal investigator, various substances will be tested in an attempt to discover neuroregenerative agents that induce regeneration in the mammalian central nervous system. Substances to be tested include tissue extracts, gene depressors, carcinogens, and agents that augment metabolism and axoplasmic synthesis. The technique involves the preparation of silver-stained retinal flat mounts after producing retinal lesions in adult mice and applying neuroregenerative substances. The method is more rapid, inexpensive and sensitive in detecting axon regeneration than are other in vivo methods.